Polysulfones containing cryptands in their backbones were prepared by the reaction of diazo-15-crown-5 and diana-18-crown-6 with divinyl sulfone. And the ion-binding properties of low molecular weight phthalimidopropyl and aminopropyl derivatives of diaza crown ethers and their polymeric versions, polyamides were investigated by conductance measurements. Changes in solution conductance of alkali metal tetraphenylborates were measured in acetone and complex formation constants were estimated from these mrasurements. The log K_ff values of aminopropy1 derivatives of diaza-18-crown-6 for potassium ion was estimated to be larger than 5, exhibiting the highest selectivity. The decrease in equivalent conductance values were much larger with polymeric cryptands, and was about 40 ohm^-1 cm² mol^-1. The break in the conductance curve was observed in the range of 2 and 3 of crown-to-cation ratio for polyamides, even though not clearly defined. The large cesium ion was not complected by the polymers of 15-crown-5 ether moiety.